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Commit b55878c90ab92a24 ("perf test: Add test for branch stack
sampling") added test for branch stack sampling. There is a sanity check
in the beginning to skip the test if the hardware doesn't support branch
stack sampling.
Snippet
<<>>
skip the test if the hardware doesn't support branch stack sampling
perf record -b -o- -B true > /dev/null 2>&1 || exit 2
<<>>
But the testcase also uses branch sample types: save_type, any. if any
platform doesn't support the branch filters used in the test, the testcase
will fail. In powerpc, currently mutliple branch filters are not supported
and hence this test fails in powerpc. Fix the sanity check to look at
the support for branch filters used in this test before proceeding with
the test.
Fixes: b55878c90ab92a24 ("perf test: Add test for branch stack sampling")
Reported-by: Disha Goel <disgoel@linux.vnet.ibm.com>
Reviewed-by: Kajol Jain <kjain@linux.ibm.com>
Signed-off-by: Athira Jajeev <atrajeev@linux.vnet.ibm.com>
Cc: German Gomez <german.gomez@arm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: linuxppc-dev@lists.ozlabs.org
Cc: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nageswara R Sastry <rnsastry@linux.ibm.com>
Link: https://lore.kernel.org/r/20220921145255.20972-2-atrajeev@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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On linux-next tree 'perf test 95' ("Check branch stack sampling") was
added recently.
s390 does not support branch sampling at all and the test case fails
despite for checking branch support before hand.
The check for support of branching uses the software event named "dummy",
as seen in the line:
perf record -b -o- -e dummy -B true > /dev/null 2>&1 || exit 2
However when the branch recording is actually done, a different event is
used, as seen in the line:
perf record -o $TMPDIR/... --branch-filter any,save_type,u -- ...
The event is omitted and for "perf record" the default event is cycles,
which is not supported by s390 and this fails when executed on s390:
# perf record --branch-filter any,save_type,u -- /tmp/__perf_test.program.iDSmQ/a.out
Error:
cycles: PMU Hardware or event type doesn't support branch stack sampling.
#
Therefore fix this and use the same event cycles for testing support
and actually running the test.
Output before:
# ./perf test -Fv 95
95: Check branch stack sampling :
--- start ---
Testing user branch stack sampling
---- end ----
Check branch stack sampling: FAILED!
#
Output after:
# ./perf test -Fv 95
95: Check branch stack sampling :
--- start ---
---- end ----
Check branch stack sampling: Skip
#
Fixes: b55878c90ab92a24 ("perf test: Add test for branch stack sampling")
Reviewed-by: James Clark <james.clark@arm.com>
Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Acked-by: German Gomez <german.gomez@arm.com>
Cc: German Gomez <german.gomez@arm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Sumanth Korikkar <sumanthk@linux.ibm.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Link: https://lore.kernel.org/r/20220727141439.712582-1-tmricht@linux.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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Add a self test for branch stack sampling, to check that we get the
expected branch types, and filters behave as expected.
Suggested-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: German Gomez <german.gomez@arm.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20220705150511.473919-2-german.gomez@arm.com
Tested-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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Athira Rajeev
Thomas Richter
German Gomez